In railway freight car supporting structures of the prior art, the load is transmitted to the supporting structure at longitudinally spaced pairs of transversely spaced points making up four points in all. Generally at the location of each pair of points, there is provided a vertically extending pin for absorbing thrust in the longitudinal direction and, at each side of the pin, a vertical load-supporting structure.
While the load-supporting structures of the prior art operate satisfactorily for the most part for normal cars under normal operating conditions, in some instances the arrangements give rise to conditions under which derailments may occur. This problem is particularly severe in the case of relatively long cars, such as schnabel cars and other multi-axle cars when they are moving into a banked curve or other similar conditions. Under this condition a torsional force is applied to the supporting structure with the result that the load on a diagonal line between the high wheel moving into the curve and the rear wheel which is located on a diagonal with reference to the high wheel, increases. Correspondingly, it is reduced at the other wheels. This condition creates a tendency for the unloaded wheels to move upwardly off the rails, with the consequent danger of derailment.